2021-03-04 06:30:47

by Gustavo A. R. Silva

[permalink] [raw]
Subject: [PATCH][next] xfs: Replace one-element arrays with flexible-array members

There is a regular need in the kernel to provide a way to declare having
a dynamically sized set of trailing elements in a structure. Kernel code
should always use “flexible array members”[1] for these cases. The older
style of one-element or zero-length arrays should no longer be used[2].

Refactor the code according to the use of flexible-array members in
multiple structures, instead of one-element arrays. Also, make use of
the new struct_size() helper to properly calculate the size of multiple
structures that contain flexible-array members.

Below are the results of running xfstests for groups shutdown and log
with the following configuration in local.config:

export TEST_DEV=/dev/sda3
export TEST_DIR=/mnt/test
export SCRATCH_DEV=/dev/sda4
export SCRATCH_MNT=/mnt/scratch

The size for both partitions /dev/sda3 and /dev/sda4 is 25GB.

These are the results of running ./check -g shutdown and ./check -g
log, respectively, on 5.11.0-next-20210301 kernel _without_ this patch
applied:

[email protected]:~/git/xfstests$ time sudo ./check -g shutdown 2>&1 | tee xfs-shutdown-no-patch.out
FSTYP -- xfs (debug)
PLATFORM -- Linux/x86_64 beefy 5.11.0-next-20210301 #4 SMP Mon Mar 1 05:42:06 CST 2021
MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4
MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch

generic/042 2s ... 2s
generic/043 13s ... 13s
generic/044 14s ... 14s
generic/045 18s ... 18s
generic/046 14s ... 14s
generic/047 20s ... 22s
generic/048 51s ... 50s
generic/049 9s ... 8s
generic/050 2s ... 1s
generic/051 76s ... 75s
generic/052 1s ... 2s
generic/054 31s ... 30s
generic/055 16s ... 21s
generic/388 89s ... 75s
generic/392 5s ... 5s
generic/417 11s ... 11s
generic/461 21s ... 22s
generic/468 3s ... 3s
generic/474 1s ... 1s
generic/475 86s ... 93s
generic/505 2s ... 2s
generic/506 2s ... 2s
generic/507 [not run] file system doesn't support chattr +AsSu
generic/508 1s ... 1s
generic/530 10s ... 10s
generic/536 3s ... 2s
generic/599 1s ... 1s
generic/622 23s ... 24s
xfs/051 18s ... 18s
xfs/079 15s ... 14s
xfs/121 6s ... 16s
xfs/181 12s ... 15s
xfs/212 1s ... 3s
Ran: generic/042 generic/043 generic/044 generic/045 generic/046 generic/047 generic/048 generic/049 generic/050 generic/051 generic/052 generic/054 generic/055 generic/388 generic/392 generic/417 generic/461 generic/468 generic/474 generic/475 generic/505 generic/506 generic/507 generic/508 generic/530 generic/536 generic/599 generic/622 xfs/051 xfs/079 xfs/121 xfs/181 xfs/212
Not run: generic/507
Passed all 33 tests

[email protected]:~/git/xfstests$ time sudo ./check -g log 2>&1 | tee xfs-log-no-patch.out
FSTYP -- xfs (debug)
PLATFORM -- Linux/x86_64 beefy 5.11.0-next-20210301 #4 SMP Mon Mar 1 05:42:06 CST 2021
MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4
MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch

generic/034 1s ... 1s
generic/039 1s ... 1s
generic/040 5s ... 5s
generic/041 7s ... 7s
generic/043 13s ... 13s
generic/044 14s ... 14s
generic/045 18s ... 18s
generic/046 14s ... 14s
generic/051 76s ... 76s
generic/052 1s ... 2s
generic/054 30s ... 48s
generic/055 23s ... 15s
generic/056 1s ... 1s
generic/057 1s ... 1s
generic/059 2s ... 2s
generic/065 1s ... 1s
generic/066 1s ... 2s
generic/073 1s ... 1s
generic/090 1s ... 1s
generic/101 1s ... 1s
generic/104 1s ... 1s
generic/106 1s ... 1s
generic/107 1s ... 1s
generic/177 1s ... 1s
generic/311 67s ... 67s
generic/321 2s ... 2s
generic/322 1s ... 2s
generic/325 1s ... 1s
generic/335 1s ... 1s
generic/336 2s ... 1s
generic/341 1s ... 1s
generic/342 1s ... 1s
generic/343 1s ... 1s
generic/376 1s ... 1s
generic/388 75s ... 97s
generic/417 15s ... 12s
generic/455 [not run] This test requires a valid $LOGWRITES_DEV
generic/457 [not run] This test requires a valid $LOGWRITES_DEV
generic/475 88s ... 89s
generic/479 2s ... 2s
generic/480 1s ... 1s
generic/481 1s ... 1s
generic/483 7s ... 6s
generic/489 1s ... 1s
generic/498 1s ... 1s
generic/501 61s ... 63s
generic/502 1s ... 1s
generic/509 1s ... 1s
generic/510 1s ... 1s
generic/512 1s ... 1s
generic/520 16s ... 17s
generic/526 2s ... 1s
generic/527 0s ... 1s
generic/534 0s ... 1s
generic/535 2s ... 1s
generic/546 3s ... 3s
generic/547 2s ... 2s
generic/552 1s ... 1s
generic/557 1s ... 2s
generic/588 2s ... 1s
shared/002 9s ... 9s
xfs/011 18s ... 18s
xfs/029 1s ... 1s
xfs/051 18s ... 18s
xfs/057 23s ... 23s
xfs/079 14s ... 14s
xfs/095 1s ... 1s
xfs/119 3s ... 3s
xfs/121 6s ... 6s
xfs/141 14s ... 26s
xfs/181 14s ... 14s
xfs/216 3s ... 2s
xfs/217 2s ... 2s
xfs/439 [not run] test requires XFS bug_on_assert to be off, turn it off to run the test
Ran: generic/034 generic/039 generic/040 generic/041 generic/043 generic/044 generic/045 generic/046 generic/051 generic/052 generic/054 generic/055 generic/056 generic/057 generic/059 generic/065 generic/066 generic/073 generic/090 generic/101 generic/104 generic/106 generic/107 generic/177 generic/311 generic/321 generic/322 generic/325 generic/335 generic/336 generic/341 generic/342 generic/343 generic/376 generic/388 generic/417 generic/455 generic/457 generic/475 generic/479 generic/480 generic/481 generic/483 generic/489 generic/498 generic/501 generic/502 generic/509 generic/510 generic/512 generic/520 generic/526 generic/527 generic/534 generic/535 generic/546 generic/547 generic/552 generic/557 generic/588 shared/002 xfs/011 xfs/029 xfs/051 xfs/057 xfs/079 xfs/095 xfs/119 xfs/121 xfs/141 xfs/181 xfs/216 xfs/217 xfs/439
Not run: generic/455 generic/457 xfs/439
Passed all 74 tests

These are the results of running ./check -g shutdown and ./check -g
log, respectively, on 5.11.0-xfstests-patched-next-20210301+ kernel
_with_ this patch applied on top:

[email protected]:~/git/xfstests$ time sudo ./check -g shutdown 2>&1 | tee xfs-shutdown-patched.out
FSTYP -- xfs (debug)
PLATFORM -- Linux/x86_64 beefy 5.11.0-xfstests-patched-next-20210301+ #10 SMP Mon Mar 1 17:36:20 CST 2021
MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4
MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch

generic/042 2s ... 3s
generic/043 13s ... 12s
generic/044 14s ... 15s
generic/045 18s ... 18s
generic/046 14s ... 15s
generic/047 21s ... 21s
generic/048 51s ... 51s
generic/049 9s ... 8s
generic/050 1s ... 2s
generic/051 76s ... 77s
generic/052 6s ... 2s
generic/054 35s ... 48s
generic/055 16s ... 17s
generic/388 77s ... 73s
generic/392 7s ... 5s
generic/417 13s ... 11s
generic/461 22s ... 21s
generic/468 2s ... 3s
generic/474 2s ... 1s
generic/475 90s ... 96s
generic/505 3s ... 3s
generic/506 1s ... 2s
generic/507 [not run] file system doesn't support chattr +AsSu
generic/508 2s ... 10s
generic/530 9s ... 13s
generic/536 2s ... 1s
generic/599 1s ... 1s
generic/622 24s ... 25s
xfs/051 18s ... 18s
xfs/079 14s ... 13s
xfs/121 6s ... 8s
xfs/181 11s ... 14s
xfs/212 2s ... 1s
Ran: generic/042 generic/043 generic/044 generic/045 generic/046 generic/047 generic/048 generic/049 generic/050 generic/051 generic/052 generic/054 generic/055 generic/388 generic/392 generic/417 generic/461 generic/468 generic/474 generic/475 generic/505 generic/506 generic/507 generic/508 generic/530 generic/536 generic/599 generic/622 xfs/051 xfs/079 xfs/121 xfs/181 xfs/212
Not run: generic/507
Passed all 33 tests

[email protected]:~/git/xfstests$ time sudo ./check -g log 2>&1 | tee xfs-log-patched.out
FSTYP -- xfs (debug)
PLATFORM -- Linux/x86_64 beefy 5.11.0-xfstests-patched-next-20210301+ #10 SMP Mon Mar 1 17:36:20 CST 2021
MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4
MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch

generic/034 1s ... 1s
generic/039 1s ... 1s
generic/040 5s ... 5s
generic/041 7s ... 7s
generic/043 12s ... 13s
generic/044 15s ... 15s
generic/045 18s ... 18s
generic/046 15s ... 14s
generic/051 77s ... 76s
generic/052 2s ... 1s
generic/054 48s ... 29s
generic/055 17s ... 16s
generic/056 1s ... 1s
generic/057 1s ... 1s
generic/059 2s ... 2s
generic/065 1s ... 1s
generic/066 1s ... 1s
generic/073 1s ... 1s
generic/090 1s ... 1s
generic/101 1s ... 1s
generic/104 1s ... 1s
generic/106 1s ... 1s
generic/107 1s ... 1s
generic/177 1s ... 1s
generic/311 68s ... 68s
generic/321 2s ... 2s
generic/322 1s ... 1s
generic/325 2s ... 1s
generic/335 1s ... 1s
generic/336 1s ... 1s
generic/341 1s ... 1s
generic/342 1s ... 1s
generic/343 1s ... 1s
generic/376 1s ... 1s
generic/388 73s ... 83s
generic/417 11s ... 11s
generic/455 [not run] This test requires a valid $LOGWRITES_DEV
generic/457 [not run] This test requires a valid $LOGWRITES_DEV
generic/475 96s ... 83s
generic/479 2s
generic/480 2s ... 1s
generic/481 0s ... 1s
generic/483 7s ... 7s
generic/489 1s ... 1s
generic/498 1s ... 1s
generic/501 63s ... 61s
generic/502 1s ... 1s
generic/509 1s ... 1s
generic/510 1s ... 1s
generic/512 1s ... 1s
generic/520 16s ... 16s
generic/526 1s ... 1s
generic/527 1s ... 1s
generic/534 1s ... 1s
generic/535 1s ... 1s
generic/546 4s ... 4s
generic/547 2s ... 2s
generic/552 1s ... 1s
generic/557 1s ... 1s
generic/588 2s ... 1s
shared/002 8s ... 9s
xfs/011 18s ... 18s
xfs/029 1s ... 1s
xfs/051 18s ... 18s
xfs/057 23s ... 24s
xfs/079 13s ... 14s
xfs/095 2s ... 1s
xfs/119 3s ... 3s
xfs/121 8s ... 6s
xfs/141 18s ... 12s
xfs/181 14s ... 12s
xfs/216 3s ... 2s
xfs/217 2s ... 2s
xfs/439 [not run] test requires XFS bug_on_assert to be off, turn it off to run the test
Ran: generic/034 generic/039 generic/040 generic/041 generic/043 generic/044 generic/045 generic/046 generic/051 generic/052 generic/054 generic/055 generic/056 generic/057 generic/059 generic/065 generic/066 generic/073 generic/090 generic/101 generic/104 generic/106 generic/107 generic/177 generic/311 generic/321 generic/322 generic/325 generic/335 generic/336 generic/341 generic/342 generic/343 generic/376 generic/388 generic/417 generic/455 generic/457 generic/475 generic/479 generic/480 generic/481 generic/483 generic/489 generic/498 generic/501 generic/502 generic/509 generic/510 generic/512 generic/520 generic/526 generic/527 generic/534 generic/535 generic/546 generic/547 generic/552 generic/557 generic/588 shared/002 xfs/011 xfs/029 xfs/051 xfs/057 xfs/079 xfs/095 xfs/119 xfs/121 xfs/141 xfs/181 xfs/216 xfs/217 xfs/439
Not run: generic/455 generic/457 xfs/439
Passed all 74 tests

Notice that the test results before and after this patch is applied are
identical and successful. Other tests might need to be run in order to
verify everything is working as expected. For such tests, the intervention
of the maintainers might be needed.

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.9/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/79
Build-tested-by: kernel test robot <[email protected]>
Link: https://lore.kernel.org/lkml/603e3177.WsvTXRpcLn5wdYW6%[email protected]/
Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
fs/xfs/libxfs/xfs_log_format.h | 12 +++++------
fs/xfs/xfs_extfree_item.c | 39 +++++++++++++++-------------------
fs/xfs/xfs_ondisk.h | 8 +++----
3 files changed, 27 insertions(+), 32 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_log_format.h b/fs/xfs/libxfs/xfs_log_format.h
index 8bd00da6d2a4..9934a465b441 100644
--- a/fs/xfs/libxfs/xfs_log_format.h
+++ b/fs/xfs/libxfs/xfs_log_format.h
@@ -574,7 +574,7 @@ typedef struct xfs_efi_log_format {
uint16_t efi_size; /* size of this item */
uint32_t efi_nextents; /* # extents to free */
uint64_t efi_id; /* efi identifier */
- xfs_extent_t efi_extents[1]; /* array of extents to free */
+ xfs_extent_t efi_extents[]; /* array of extents to free */
} xfs_efi_log_format_t;

typedef struct xfs_efi_log_format_32 {
@@ -582,7 +582,7 @@ typedef struct xfs_efi_log_format_32 {
uint16_t efi_size; /* size of this item */
uint32_t efi_nextents; /* # extents to free */
uint64_t efi_id; /* efi identifier */
- xfs_extent_32_t efi_extents[1]; /* array of extents to free */
+ xfs_extent_32_t efi_extents[]; /* array of extents to free */
} __attribute__((packed)) xfs_efi_log_format_32_t;

typedef struct xfs_efi_log_format_64 {
@@ -590,7 +590,7 @@ typedef struct xfs_efi_log_format_64 {
uint16_t efi_size; /* size of this item */
uint32_t efi_nextents; /* # extents to free */
uint64_t efi_id; /* efi identifier */
- xfs_extent_64_t efi_extents[1]; /* array of extents to free */
+ xfs_extent_64_t efi_extents[]; /* array of extents to free */
} xfs_efi_log_format_64_t;

/*
@@ -603,7 +603,7 @@ typedef struct xfs_efd_log_format {
uint16_t efd_size; /* size of this item */
uint32_t efd_nextents; /* # of extents freed */
uint64_t efd_efi_id; /* id of corresponding efi */
- xfs_extent_t efd_extents[1]; /* array of extents freed */
+ xfs_extent_t efd_extents[]; /* array of extents freed */
} xfs_efd_log_format_t;

typedef struct xfs_efd_log_format_32 {
@@ -611,7 +611,7 @@ typedef struct xfs_efd_log_format_32 {
uint16_t efd_size; /* size of this item */
uint32_t efd_nextents; /* # of extents freed */
uint64_t efd_efi_id; /* id of corresponding efi */
- xfs_extent_32_t efd_extents[1]; /* array of extents freed */
+ xfs_extent_32_t efd_extents[]; /* array of extents freed */
} __attribute__((packed)) xfs_efd_log_format_32_t;

typedef struct xfs_efd_log_format_64 {
@@ -619,7 +619,7 @@ typedef struct xfs_efd_log_format_64 {
uint16_t efd_size; /* size of this item */
uint32_t efd_nextents; /* # of extents freed */
uint64_t efd_efi_id; /* id of corresponding efi */
- xfs_extent_64_t efd_extents[1]; /* array of extents freed */
+ xfs_extent_64_t efd_extents[]; /* array of extents freed */
} xfs_efd_log_format_64_t;

/*
diff --git a/fs/xfs/xfs_extfree_item.c b/fs/xfs/xfs_extfree_item.c
index 93223ebb3372..5ed3ea93071c 100644
--- a/fs/xfs/xfs_extfree_item.c
+++ b/fs/xfs/xfs_extfree_item.c
@@ -73,8 +73,8 @@ static inline int
xfs_efi_item_sizeof(
struct xfs_efi_log_item *efip)
{
- return sizeof(struct xfs_efi_log_format) +
- (efip->efi_format.efi_nextents - 1) * sizeof(xfs_extent_t);
+ return struct_size(&efip->efi_format, efi_extents,
+ efip->efi_format.efi_nextents);
}

STATIC void
@@ -153,17 +153,14 @@ xfs_efi_init(

{
struct xfs_efi_log_item *efip;
- uint size;

ASSERT(nextents > 0);
- if (nextents > XFS_EFI_MAX_FAST_EXTENTS) {
- size = (uint)(sizeof(struct xfs_efi_log_item) +
- ((nextents - 1) * sizeof(xfs_extent_t)));
- efip = kmem_zalloc(size, 0);
- } else {
+ if (nextents > XFS_EFI_MAX_FAST_EXTENTS)
+ efip = kmem_zalloc(struct_size(efip, efi_format.efi_extents,
+ nextents), 0);
+ else
efip = kmem_cache_zalloc(xfs_efi_zone,
GFP_KERNEL | __GFP_NOFAIL);
- }

xfs_log_item_init(mp, &efip->efi_item, XFS_LI_EFI, &xfs_efi_item_ops);
efip->efi_format.efi_nextents = nextents;
@@ -186,12 +183,12 @@ xfs_efi_copy_format(xfs_log_iovec_t *buf, xfs_efi_log_format_t *dst_efi_fmt)
{
xfs_efi_log_format_t *src_efi_fmt = buf->i_addr;
uint i;
- uint len = sizeof(xfs_efi_log_format_t) +
- (src_efi_fmt->efi_nextents - 1) * sizeof(xfs_extent_t);
+ size_t len = struct_size(src_efi_fmt, efi_extents,
+ src_efi_fmt->efi_nextents);
uint len32 = sizeof(xfs_efi_log_format_32_t) +
- (src_efi_fmt->efi_nextents - 1) * sizeof(xfs_extent_32_t);
+ src_efi_fmt->efi_nextents * sizeof(xfs_extent_32_t);
uint len64 = sizeof(xfs_efi_log_format_64_t) +
- (src_efi_fmt->efi_nextents - 1) * sizeof(xfs_extent_64_t);
+ src_efi_fmt->efi_nextents * sizeof(xfs_extent_64_t);

if (buf->i_len == len) {
memcpy((char *)dst_efi_fmt, (char*)src_efi_fmt, len);
@@ -254,7 +251,7 @@ xfs_efd_item_sizeof(
struct xfs_efd_log_item *efdp)
{
return sizeof(xfs_efd_log_format_t) +
- (efdp->efd_format.efd_nextents - 1) * sizeof(xfs_extent_t);
+ efdp->efd_format.efd_nextents * sizeof(xfs_extent_t);
}

STATIC void
@@ -328,14 +325,12 @@ xfs_trans_get_efd(

ASSERT(nextents > 0);

- if (nextents > XFS_EFD_MAX_FAST_EXTENTS) {
- efdp = kmem_zalloc(sizeof(struct xfs_efd_log_item) +
- (nextents - 1) * sizeof(struct xfs_extent),
- 0);
- } else {
+ if (nextents > XFS_EFD_MAX_FAST_EXTENTS)
+ efdp = kmem_zalloc(struct_size(efip, efi_format.efi_extents,
+ nextents), 0);
+ else
efdp = kmem_cache_zalloc(xfs_efd_zone,
GFP_KERNEL | __GFP_NOFAIL);
- }

xfs_log_item_init(tp->t_mountp, &efdp->efd_item, XFS_LI_EFD,
&xfs_efd_item_ops);
@@ -747,9 +742,9 @@ xlog_recover_efd_commit_pass2(

efd_formatp = item->ri_buf[0].i_addr;
ASSERT((item->ri_buf[0].i_len == (sizeof(xfs_efd_log_format_32_t) +
- ((efd_formatp->efd_nextents - 1) * sizeof(xfs_extent_32_t)))) ||
+ (efd_formatp->efd_nextents * sizeof(xfs_extent_32_t)))) ||
(item->ri_buf[0].i_len == (sizeof(xfs_efd_log_format_64_t) +
- ((efd_formatp->efd_nextents - 1) * sizeof(xfs_extent_64_t)))));
+ (efd_formatp->efd_nextents * sizeof(xfs_extent_64_t)))));

xlog_recover_release_intent(log, XFS_LI_EFI, efd_formatp->efd_efi_id);
return 0;
diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
index 0aa87c210104..f58e0510385a 100644
--- a/fs/xfs/xfs_ondisk.h
+++ b/fs/xfs/xfs_ondisk.h
@@ -118,10 +118,10 @@ xfs_check_ondisk_structs(void)
/* log structures */
XFS_CHECK_STRUCT_SIZE(struct xfs_buf_log_format, 88);
XFS_CHECK_STRUCT_SIZE(struct xfs_dq_logformat, 24);
- XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_32, 28);
- XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_64, 32);
- XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_32, 28);
- XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_64, 32);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_32, 16);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_64, 16);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_32, 16);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_64, 16);
XFS_CHECK_STRUCT_SIZE(struct xfs_extent_32, 12);
XFS_CHECK_STRUCT_SIZE(struct xfs_extent_64, 16);
XFS_CHECK_STRUCT_SIZE(struct xfs_log_dinode, 176);
--
2.27.0


2021-03-09 17:44:06

by Darrick J. Wong

[permalink] [raw]
Subject: Re: [PATCH][next] xfs: Replace one-element arrays with flexible-array members

On Tue, Mar 02, 2021 at 09:05:58AM -0600, Gustavo A. R. Silva wrote:
> There is a regular need in the kernel to provide a way to declare having
> a dynamically sized set of trailing elements in a structure. Kernel code
> should always use “flexible array members”[1] for these cases. The older
> style of one-element or zero-length arrays should no longer be used[2].
>
> Refactor the code according to the use of flexible-array members in
> multiple structures, instead of one-element arrays. Also, make use of
> the new struct_size() helper to properly calculate the size of multiple
> structures that contain flexible-array members.
>
> Below are the results of running xfstests for groups shutdown and log
> with the following configuration in local.config:
>
> export TEST_DEV=/dev/sda3
> export TEST_DIR=/mnt/test
> export SCRATCH_DEV=/dev/sda4
> export SCRATCH_MNT=/mnt/scratch
>
> The size for both partitions /dev/sda3 and /dev/sda4 is 25GB.
>
> These are the results of running ./check -g shutdown and ./check -g
> log, respectively, on 5.11.0-next-20210301 kernel _without_ this patch
> applied:
>
> [email protected]:~/git/xfstests$ time sudo ./check -g shutdown 2>&1 | tee xfs-shutdown-no-patch.out
> FSTYP -- xfs (debug)
> PLATFORM -- Linux/x86_64 beefy 5.11.0-next-20210301 #4 SMP Mon Mar 1 05:42:06 CST 2021
> MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4
> MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch
>
> generic/042 2s ... 2s
> generic/043 13s ... 13s
> generic/044 14s ... 14s
> generic/045 18s ... 18s
> generic/046 14s ... 14s
> generic/047 20s ... 22s
> generic/048 51s ... 50s
> generic/049 9s ... 8s
> generic/050 2s ... 1s
> generic/051 76s ... 75s
> generic/052 1s ... 2s
> generic/054 31s ... 30s
> generic/055 16s ... 21s
> generic/388 89s ... 75s
> generic/392 5s ... 5s
> generic/417 11s ... 11s
> generic/461 21s ... 22s
> generic/468 3s ... 3s
> generic/474 1s ... 1s
> generic/475 86s ... 93s
> generic/505 2s ... 2s
> generic/506 2s ... 2s
> generic/507 [not run] file system doesn't support chattr +AsSu
> generic/508 1s ... 1s
> generic/530 10s ... 10s
> generic/536 3s ... 2s
> generic/599 1s ... 1s
> generic/622 23s ... 24s
> xfs/051 18s ... 18s
> xfs/079 15s ... 14s
> xfs/121 6s ... 16s
> xfs/181 12s ... 15s
> xfs/212 1s ... 3s
> Ran: generic/042 generic/043 generic/044 generic/045 generic/046 generic/047 generic/048 generic/049 generic/050 generic/051 generic/052 generic/054 generic/055 generic/388 generic/392 generic/417 generic/461 generic/468 generic/474 generic/475 generic/505 generic/506 generic/507 generic/508 generic/530 generic/536 generic/599 generic/622 xfs/051 xfs/079 xfs/121 xfs/181 xfs/212
> Not run: generic/507
> Passed all 33 tests
>
> [email protected]:~/git/xfstests$ time sudo ./check -g log 2>&1 | tee xfs-log-no-patch.out
> FSTYP -- xfs (debug)
> PLATFORM -- Linux/x86_64 beefy 5.11.0-next-20210301 #4 SMP Mon Mar 1 05:42:06 CST 2021
> MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4
> MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch
>
> generic/034 1s ... 1s
> generic/039 1s ... 1s
> generic/040 5s ... 5s
> generic/041 7s ... 7s
> generic/043 13s ... 13s
> generic/044 14s ... 14s
> generic/045 18s ... 18s
> generic/046 14s ... 14s
> generic/051 76s ... 76s
> generic/052 1s ... 2s
> generic/054 30s ... 48s
> generic/055 23s ... 15s
> generic/056 1s ... 1s
> generic/057 1s ... 1s
> generic/059 2s ... 2s
> generic/065 1s ... 1s
> generic/066 1s ... 2s
> generic/073 1s ... 1s
> generic/090 1s ... 1s
> generic/101 1s ... 1s
> generic/104 1s ... 1s
> generic/106 1s ... 1s
> generic/107 1s ... 1s
> generic/177 1s ... 1s
> generic/311 67s ... 67s
> generic/321 2s ... 2s
> generic/322 1s ... 2s
> generic/325 1s ... 1s
> generic/335 1s ... 1s
> generic/336 2s ... 1s
> generic/341 1s ... 1s
> generic/342 1s ... 1s
> generic/343 1s ... 1s
> generic/376 1s ... 1s
> generic/388 75s ... 97s
> generic/417 15s ... 12s
> generic/455 [not run] This test requires a valid $LOGWRITES_DEV
> generic/457 [not run] This test requires a valid $LOGWRITES_DEV
> generic/475 88s ... 89s
> generic/479 2s ... 2s
> generic/480 1s ... 1s
> generic/481 1s ... 1s
> generic/483 7s ... 6s
> generic/489 1s ... 1s
> generic/498 1s ... 1s
> generic/501 61s ... 63s
> generic/502 1s ... 1s
> generic/509 1s ... 1s
> generic/510 1s ... 1s
> generic/512 1s ... 1s
> generic/520 16s ... 17s
> generic/526 2s ... 1s
> generic/527 0s ... 1s
> generic/534 0s ... 1s
> generic/535 2s ... 1s
> generic/546 3s ... 3s
> generic/547 2s ... 2s
> generic/552 1s ... 1s
> generic/557 1s ... 2s
> generic/588 2s ... 1s
> shared/002 9s ... 9s
> xfs/011 18s ... 18s
> xfs/029 1s ... 1s
> xfs/051 18s ... 18s
> xfs/057 23s ... 23s
> xfs/079 14s ... 14s
> xfs/095 1s ... 1s
> xfs/119 3s ... 3s
> xfs/121 6s ... 6s
> xfs/141 14s ... 26s
> xfs/181 14s ... 14s
> xfs/216 3s ... 2s
> xfs/217 2s ... 2s
> xfs/439 [not run] test requires XFS bug_on_assert to be off, turn it off to run the test
> Ran: generic/034 generic/039 generic/040 generic/041 generic/043 generic/044 generic/045 generic/046 generic/051 generic/052 generic/054 generic/055 generic/056 generic/057 generic/059 generic/065 generic/066 generic/073 generic/090 generic/101 generic/104 generic/106 generic/107 generic/177 generic/311 generic/321 generic/322 generic/325 generic/335 generic/336 generic/341 generic/342 generic/343 generic/376 generic/388 generic/417 generic/455 generic/457 generic/475 generic/479 generic/480 generic/481 generic/483 generic/489 generic/498 generic/501 generic/502 generic/509 generic/510 generic/512 generic/520 generic/526 generic/527 generic/534 generic/535 generic/546 generic/547 generic/552 generic/557 generic/588 shared/002 xfs/011 xfs/029 xfs/051 xfs/057 xfs/079 xfs/095 xfs/119 xfs/121 xfs/141 xfs/181 xfs/216 xfs/217 xfs/439
> Not run: generic/455 generic/457 xfs/439
> Passed all 74 tests
>
> These are the results of running ./check -g shutdown and ./check -g
> log, respectively, on 5.11.0-xfstests-patched-next-20210301+ kernel
> _with_ this patch applied on top:
>
> [email protected]:~/git/xfstests$ time sudo ./check -g shutdown 2>&1 | tee xfs-shutdown-patched.out
> FSTYP -- xfs (debug)
> PLATFORM -- Linux/x86_64 beefy 5.11.0-xfstests-patched-next-20210301+ #10 SMP Mon Mar 1 17:36:20 CST 2021
> MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4
> MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch
>
> generic/042 2s ... 3s
> generic/043 13s ... 12s
> generic/044 14s ... 15s
> generic/045 18s ... 18s
> generic/046 14s ... 15s
> generic/047 21s ... 21s
> generic/048 51s ... 51s
> generic/049 9s ... 8s
> generic/050 1s ... 2s
> generic/051 76s ... 77s
> generic/052 6s ... 2s
> generic/054 35s ... 48s
> generic/055 16s ... 17s
> generic/388 77s ... 73s
> generic/392 7s ... 5s
> generic/417 13s ... 11s
> generic/461 22s ... 21s
> generic/468 2s ... 3s
> generic/474 2s ... 1s
> generic/475 90s ... 96s
> generic/505 3s ... 3s
> generic/506 1s ... 2s
> generic/507 [not run] file system doesn't support chattr +AsSu
> generic/508 2s ... 10s
> generic/530 9s ... 13s
> generic/536 2s ... 1s
> generic/599 1s ... 1s
> generic/622 24s ... 25s
> xfs/051 18s ... 18s
> xfs/079 14s ... 13s
> xfs/121 6s ... 8s
> xfs/181 11s ... 14s
> xfs/212 2s ... 1s
> Ran: generic/042 generic/043 generic/044 generic/045 generic/046 generic/047 generic/048 generic/049 generic/050 generic/051 generic/052 generic/054 generic/055 generic/388 generic/392 generic/417 generic/461 generic/468 generic/474 generic/475 generic/505 generic/506 generic/507 generic/508 generic/530 generic/536 generic/599 generic/622 xfs/051 xfs/079 xfs/121 xfs/181 xfs/212
> Not run: generic/507
> Passed all 33 tests
>
> [email protected]:~/git/xfstests$ time sudo ./check -g log 2>&1 | tee xfs-log-patched.out
> FSTYP -- xfs (debug)
> PLATFORM -- Linux/x86_64 beefy 5.11.0-xfstests-patched-next-20210301+ #10 SMP Mon Mar 1 17:36:20 CST 2021
> MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4
> MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch
>
> generic/034 1s ... 1s
> generic/039 1s ... 1s
> generic/040 5s ... 5s
> generic/041 7s ... 7s
> generic/043 12s ... 13s
> generic/044 15s ... 15s
> generic/045 18s ... 18s
> generic/046 15s ... 14s
> generic/051 77s ... 76s
> generic/052 2s ... 1s
> generic/054 48s ... 29s
> generic/055 17s ... 16s
> generic/056 1s ... 1s
> generic/057 1s ... 1s
> generic/059 2s ... 2s
> generic/065 1s ... 1s
> generic/066 1s ... 1s
> generic/073 1s ... 1s
> generic/090 1s ... 1s
> generic/101 1s ... 1s
> generic/104 1s ... 1s
> generic/106 1s ... 1s
> generic/107 1s ... 1s
> generic/177 1s ... 1s
> generic/311 68s ... 68s
> generic/321 2s ... 2s
> generic/322 1s ... 1s
> generic/325 2s ... 1s
> generic/335 1s ... 1s
> generic/336 1s ... 1s
> generic/341 1s ... 1s
> generic/342 1s ... 1s
> generic/343 1s ... 1s
> generic/376 1s ... 1s
> generic/388 73s ... 83s
> generic/417 11s ... 11s
> generic/455 [not run] This test requires a valid $LOGWRITES_DEV
> generic/457 [not run] This test requires a valid $LOGWRITES_DEV
> generic/475 96s ... 83s
> generic/479 2s
> generic/480 2s ... 1s
> generic/481 0s ... 1s
> generic/483 7s ... 7s
> generic/489 1s ... 1s
> generic/498 1s ... 1s
> generic/501 63s ... 61s
> generic/502 1s ... 1s
> generic/509 1s ... 1s
> generic/510 1s ... 1s
> generic/512 1s ... 1s
> generic/520 16s ... 16s
> generic/526 1s ... 1s
> generic/527 1s ... 1s
> generic/534 1s ... 1s
> generic/535 1s ... 1s
> generic/546 4s ... 4s
> generic/547 2s ... 2s
> generic/552 1s ... 1s
> generic/557 1s ... 1s
> generic/588 2s ... 1s
> shared/002 8s ... 9s
> xfs/011 18s ... 18s
> xfs/029 1s ... 1s
> xfs/051 18s ... 18s
> xfs/057 23s ... 24s
> xfs/079 13s ... 14s
> xfs/095 2s ... 1s
> xfs/119 3s ... 3s
> xfs/121 8s ... 6s
> xfs/141 18s ... 12s
> xfs/181 14s ... 12s
> xfs/216 3s ... 2s
> xfs/217 2s ... 2s
> xfs/439 [not run] test requires XFS bug_on_assert to be off, turn it off to run the test
> Ran: generic/034 generic/039 generic/040 generic/041 generic/043 generic/044 generic/045 generic/046 generic/051 generic/052 generic/054 generic/055 generic/056 generic/057 generic/059 generic/065 generic/066 generic/073 generic/090 generic/101 generic/104 generic/106 generic/107 generic/177 generic/311 generic/321 generic/322 generic/325 generic/335 generic/336 generic/341 generic/342 generic/343 generic/376 generic/388 generic/417 generic/455 generic/457 generic/475 generic/479 generic/480 generic/481 generic/483 generic/489 generic/498 generic/501 generic/502 generic/509 generic/510 generic/512 generic/520 generic/526 generic/527 generic/534 generic/535 generic/546 generic/547 generic/552 generic/557 generic/588 shared/002 xfs/011 xfs/029 xfs/051 xfs/057 xfs/079 xfs/095 xfs/119 xfs/121 xfs/141 xfs/181 xfs/216 xfs/217 xfs/439
> Not run: generic/455 generic/457 xfs/439
> Passed all 74 tests
>
> Notice that the test results before and after this patch is applied are
> identical and successful. Other tests might need to be run in order to
> verify everything is working as expected. For such tests, the intervention
> of the maintainers might be needed.
>
> [1] https://en.wikipedia.org/wiki/Flexible_array_member
> [2] https://www.kernel.org/doc/html/v5.9/process/deprecated.html#zero-length-and-one-element-arrays
>
> Link: https://github.com/KSPP/linux/issues/79
> Build-tested-by: kernel test robot <[email protected]>
> Link: https://lore.kernel.org/lkml/603e3177.WsvTXRpcLn5wdYW6%[email protected]/
> Signed-off-by: Gustavo A. R. Silva <[email protected]>
> ---
> fs/xfs/libxfs/xfs_log_format.h | 12 +++++------
> fs/xfs/xfs_extfree_item.c | 39 +++++++++++++++-------------------
> fs/xfs/xfs_ondisk.h | 8 +++----
> 3 files changed, 27 insertions(+), 32 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_log_format.h b/fs/xfs/libxfs/xfs_log_format.h
> index 8bd00da6d2a4..9934a465b441 100644
> --- a/fs/xfs/libxfs/xfs_log_format.h
> +++ b/fs/xfs/libxfs/xfs_log_format.h
> @@ -574,7 +574,7 @@ typedef struct xfs_efi_log_format {
> uint16_t efi_size; /* size of this item */
> uint32_t efi_nextents; /* # extents to free */
> uint64_t efi_id; /* efi identifier */
> - xfs_extent_t efi_extents[1]; /* array of extents to free */
> + xfs_extent_t efi_extents[]; /* array of extents to free */
> } xfs_efi_log_format_t;
>
> typedef struct xfs_efi_log_format_32 {
> @@ -582,7 +582,7 @@ typedef struct xfs_efi_log_format_32 {
> uint16_t efi_size; /* size of this item */
> uint32_t efi_nextents; /* # extents to free */
> uint64_t efi_id; /* efi identifier */
> - xfs_extent_32_t efi_extents[1]; /* array of extents to free */
> + xfs_extent_32_t efi_extents[]; /* array of extents to free */
> } __attribute__((packed)) xfs_efi_log_format_32_t;
>
> typedef struct xfs_efi_log_format_64 {
> @@ -590,7 +590,7 @@ typedef struct xfs_efi_log_format_64 {
> uint16_t efi_size; /* size of this item */
> uint32_t efi_nextents; /* # extents to free */
> uint64_t efi_id; /* efi identifier */
> - xfs_extent_64_t efi_extents[1]; /* array of extents to free */
> + xfs_extent_64_t efi_extents[]; /* array of extents to free */
> } xfs_efi_log_format_64_t;
>
> /*
> @@ -603,7 +603,7 @@ typedef struct xfs_efd_log_format {
> uint16_t efd_size; /* size of this item */
> uint32_t efd_nextents; /* # of extents freed */
> uint64_t efd_efi_id; /* id of corresponding efi */
> - xfs_extent_t efd_extents[1]; /* array of extents freed */
> + xfs_extent_t efd_extents[]; /* array of extents freed */
> } xfs_efd_log_format_t;
>
> typedef struct xfs_efd_log_format_32 {
> @@ -611,7 +611,7 @@ typedef struct xfs_efd_log_format_32 {
> uint16_t efd_size; /* size of this item */
> uint32_t efd_nextents; /* # of extents freed */
> uint64_t efd_efi_id; /* id of corresponding efi */
> - xfs_extent_32_t efd_extents[1]; /* array of extents freed */
> + xfs_extent_32_t efd_extents[]; /* array of extents freed */
> } __attribute__((packed)) xfs_efd_log_format_32_t;
>
> typedef struct xfs_efd_log_format_64 {
> @@ -619,7 +619,7 @@ typedef struct xfs_efd_log_format_64 {
> uint16_t efd_size; /* size of this item */
> uint32_t efd_nextents; /* # of extents freed */
> uint64_t efd_efi_id; /* id of corresponding efi */
> - xfs_extent_64_t efd_extents[1]; /* array of extents freed */
> + xfs_extent_64_t efd_extents[]; /* array of extents freed */
> } xfs_efd_log_format_64_t;
>
> /*
> diff --git a/fs/xfs/xfs_extfree_item.c b/fs/xfs/xfs_extfree_item.c
> index 93223ebb3372..5ed3ea93071c 100644
> --- a/fs/xfs/xfs_extfree_item.c
> +++ b/fs/xfs/xfs_extfree_item.c
> @@ -73,8 +73,8 @@ static inline int
> xfs_efi_item_sizeof(
> struct xfs_efi_log_item *efip)
> {
> - return sizeof(struct xfs_efi_log_format) +
> - (efip->efi_format.efi_nextents - 1) * sizeof(xfs_extent_t);
> + return struct_size(&efip->efi_format, efi_extents,
> + efip->efi_format.efi_nextents);
> }
>
> STATIC void
> @@ -153,17 +153,14 @@ xfs_efi_init(
>
> {
> struct xfs_efi_log_item *efip;
> - uint size;
>
> ASSERT(nextents > 0);
> - if (nextents > XFS_EFI_MAX_FAST_EXTENTS) {
> - size = (uint)(sizeof(struct xfs_efi_log_item) +
> - ((nextents - 1) * sizeof(xfs_extent_t)));
> - efip = kmem_zalloc(size, 0);
> - } else {
> + if (nextents > XFS_EFI_MAX_FAST_EXTENTS)
> + efip = kmem_zalloc(struct_size(efip, efi_format.efi_extents,
> + nextents), 0);
> + else
> efip = kmem_cache_zalloc(xfs_efi_zone,
> GFP_KERNEL | __GFP_NOFAIL);
> - }
>
> xfs_log_item_init(mp, &efip->efi_item, XFS_LI_EFI, &xfs_efi_item_ops);
> efip->efi_format.efi_nextents = nextents;
> @@ -186,12 +183,12 @@ xfs_efi_copy_format(xfs_log_iovec_t *buf, xfs_efi_log_format_t *dst_efi_fmt)
> {
> xfs_efi_log_format_t *src_efi_fmt = buf->i_addr;
> uint i;
> - uint len = sizeof(xfs_efi_log_format_t) +
> - (src_efi_fmt->efi_nextents - 1) * sizeof(xfs_extent_t);
> + size_t len = struct_size(src_efi_fmt, efi_extents,
> + src_efi_fmt->efi_nextents);
> uint len32 = sizeof(xfs_efi_log_format_32_t) +
> - (src_efi_fmt->efi_nextents - 1) * sizeof(xfs_extent_32_t);
> + src_efi_fmt->efi_nextents * sizeof(xfs_extent_32_t);

Shouldn't these be converted to struct_size() too?

It seems to work all right for casted NULL pointers, and then we get all
the typechecking and multiplication overflow checking, e.g.:

size_t len64 = struct_size((struct xfs_efi_log_format_32 *)NULL,
efi_extents src_efi_fmt->efi_nextents);

--D

> uint len64 = sizeof(xfs_efi_log_format_64_t) +
> - (src_efi_fmt->efi_nextents - 1) * sizeof(xfs_extent_64_t);
> + src_efi_fmt->efi_nextents * sizeof(xfs_extent_64_t);
>
> if (buf->i_len == len) {
> memcpy((char *)dst_efi_fmt, (char*)src_efi_fmt, len);
> @@ -254,7 +251,7 @@ xfs_efd_item_sizeof(
> struct xfs_efd_log_item *efdp)
> {
> return sizeof(xfs_efd_log_format_t) +
> - (efdp->efd_format.efd_nextents - 1) * sizeof(xfs_extent_t);
> + efdp->efd_format.efd_nextents * sizeof(xfs_extent_t);
> }
>
> STATIC void
> @@ -328,14 +325,12 @@ xfs_trans_get_efd(
>
> ASSERT(nextents > 0);
>
> - if (nextents > XFS_EFD_MAX_FAST_EXTENTS) {
> - efdp = kmem_zalloc(sizeof(struct xfs_efd_log_item) +
> - (nextents - 1) * sizeof(struct xfs_extent),
> - 0);
> - } else {
> + if (nextents > XFS_EFD_MAX_FAST_EXTENTS)
> + efdp = kmem_zalloc(struct_size(efip, efi_format.efi_extents,
> + nextents), 0);
> + else
> efdp = kmem_cache_zalloc(xfs_efd_zone,
> GFP_KERNEL | __GFP_NOFAIL);
> - }
>
> xfs_log_item_init(tp->t_mountp, &efdp->efd_item, XFS_LI_EFD,
> &xfs_efd_item_ops);
> @@ -747,9 +742,9 @@ xlog_recover_efd_commit_pass2(
>
> efd_formatp = item->ri_buf[0].i_addr;
> ASSERT((item->ri_buf[0].i_len == (sizeof(xfs_efd_log_format_32_t) +
> - ((efd_formatp->efd_nextents - 1) * sizeof(xfs_extent_32_t)))) ||
> + (efd_formatp->efd_nextents * sizeof(xfs_extent_32_t)))) ||
> (item->ri_buf[0].i_len == (sizeof(xfs_efd_log_format_64_t) +
> - ((efd_formatp->efd_nextents - 1) * sizeof(xfs_extent_64_t)))));
> + (efd_formatp->efd_nextents * sizeof(xfs_extent_64_t)))));
>
> xlog_recover_release_intent(log, XFS_LI_EFI, efd_formatp->efd_efi_id);
> return 0;
> diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
> index 0aa87c210104..f58e0510385a 100644
> --- a/fs/xfs/xfs_ondisk.h
> +++ b/fs/xfs/xfs_ondisk.h
> @@ -118,10 +118,10 @@ xfs_check_ondisk_structs(void)
> /* log structures */
> XFS_CHECK_STRUCT_SIZE(struct xfs_buf_log_format, 88);
> XFS_CHECK_STRUCT_SIZE(struct xfs_dq_logformat, 24);
> - XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_32, 28);
> - XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_64, 32);
> - XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_32, 28);
> - XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_64, 32);
> + XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_32, 16);
> + XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_64, 16);
> + XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_32, 16);
> + XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_64, 16);
> XFS_CHECK_STRUCT_SIZE(struct xfs_extent_32, 12);
> XFS_CHECK_STRUCT_SIZE(struct xfs_extent_64, 16);
> XFS_CHECK_STRUCT_SIZE(struct xfs_log_dinode, 176);
> --
> 2.27.0
>

2021-03-09 20:23:03

by Gustavo A. R. Silva

[permalink] [raw]
Subject: Re: [PATCH][next] xfs: Replace one-element arrays with flexible-array members

Hi Darrick,

Please, see my comments below...

On 3/9/21 11:42, Darrick J. Wong wrote:
> On Tue, Mar 02, 2021 at 09:05:58AM -0600, Gustavo A. R. Silva wrote:
>> There is a regular need in the kernel to provide a way to declare having
>> a dynamically sized set of trailing elements in a structure. Kernel code
>> should always use “flexible array members”[1] for these cases. The older
>> style of one-element or zero-length arrays should no longer be used[2].
>>
>> Refactor the code according to the use of flexible-array members in
>> multiple structures, instead of one-element arrays. Also, make use of
>> the new struct_size() helper to properly calculate the size of multiple
>> structures that contain flexible-array members.
>>
>> Below are the results of running xfstests for groups shutdown and log
>> with the following configuration in local.config:
>>
>> export TEST_DEV=/dev/sda3
>> export TEST_DIR=/mnt/test
>> export SCRATCH_DEV=/dev/sda4
>> export SCRATCH_MNT=/mnt/scratch
>>
>> The size for both partitions /dev/sda3 and /dev/sda4 is 25GB.
>>
>> These are the results of running ./check -g shutdown and ./check -g
>> log, respectively, on 5.11.0-next-20210301 kernel _without_ this patch
>> applied:
>>
>> [email protected]:~/git/xfstests$ time sudo ./check -g shutdown 2>&1 | tee xfs-shutdown-no-patch.out
>> FSTYP -- xfs (debug)
>> PLATFORM -- Linux/x86_64 beefy 5.11.0-next-20210301 #4 SMP Mon Mar 1 05:42:06 CST 2021
>> MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4
>> MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch
>>
>> generic/042 2s ... 2s
>> generic/043 13s ... 13s
>> generic/044 14s ... 14s
>> generic/045 18s ... 18s
>> generic/046 14s ... 14s
>> generic/047 20s ... 22s
>> generic/048 51s ... 50s
>> generic/049 9s ... 8s
>> generic/050 2s ... 1s
>> generic/051 76s ... 75s
>> generic/052 1s ... 2s
>> generic/054 31s ... 30s
>> generic/055 16s ... 21s
>> generic/388 89s ... 75s
>> generic/392 5s ... 5s
>> generic/417 11s ... 11s
>> generic/461 21s ... 22s
>> generic/468 3s ... 3s
>> generic/474 1s ... 1s
>> generic/475 86s ... 93s
>> generic/505 2s ... 2s
>> generic/506 2s ... 2s
>> generic/507 [not run] file system doesn't support chattr +AsSu
>> generic/508 1s ... 1s
>> generic/530 10s ... 10s
>> generic/536 3s ... 2s
>> generic/599 1s ... 1s
>> generic/622 23s ... 24s
>> xfs/051 18s ... 18s
>> xfs/079 15s ... 14s
>> xfs/121 6s ... 16s
>> xfs/181 12s ... 15s
>> xfs/212 1s ... 3s
>> Ran: generic/042 generic/043 generic/044 generic/045 generic/046 generic/047 generic/048 generic/049 generic/050 generic/051 generic/052 generic/054 generic/055 generic/388 generic/392 generic/417 generic/461 generic/468 generic/474 generic/475 generic/505 generic/506 generic/507 generic/508 generic/530 generic/536 generic/599 generic/622 xfs/051 xfs/079 xfs/121 xfs/181 xfs/212
>> Not run: generic/507
>> Passed all 33 tests
>>
>> [email protected]:~/git/xfstests$ time sudo ./check -g log 2>&1 | tee xfs-log-no-patch.out
>> FSTYP -- xfs (debug)
>> PLATFORM -- Linux/x86_64 beefy 5.11.0-next-20210301 #4 SMP Mon Mar 1 05:42:06 CST 2021
>> MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4
>> MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch
>>
>> generic/034 1s ... 1s
>> generic/039 1s ... 1s
>> generic/040 5s ... 5s
>> generic/041 7s ... 7s
>> generic/043 13s ... 13s
>> generic/044 14s ... 14s
>> generic/045 18s ... 18s
>> generic/046 14s ... 14s
>> generic/051 76s ... 76s
>> generic/052 1s ... 2s
>> generic/054 30s ... 48s
>> generic/055 23s ... 15s
>> generic/056 1s ... 1s
>> generic/057 1s ... 1s
>> generic/059 2s ... 2s
>> generic/065 1s ... 1s
>> generic/066 1s ... 2s
>> generic/073 1s ... 1s
>> generic/090 1s ... 1s
>> generic/101 1s ... 1s
>> generic/104 1s ... 1s
>> generic/106 1s ... 1s
>> generic/107 1s ... 1s
>> generic/177 1s ... 1s
>> generic/311 67s ... 67s
>> generic/321 2s ... 2s
>> generic/322 1s ... 2s
>> generic/325 1s ... 1s
>> generic/335 1s ... 1s
>> generic/336 2s ... 1s
>> generic/341 1s ... 1s
>> generic/342 1s ... 1s
>> generic/343 1s ... 1s
>> generic/376 1s ... 1s
>> generic/388 75s ... 97s
>> generic/417 15s ... 12s
>> generic/455 [not run] This test requires a valid $LOGWRITES_DEV
>> generic/457 [not run] This test requires a valid $LOGWRITES_DEV
>> generic/475 88s ... 89s
>> generic/479 2s ... 2s
>> generic/480 1s ... 1s
>> generic/481 1s ... 1s
>> generic/483 7s ... 6s
>> generic/489 1s ... 1s
>> generic/498 1s ... 1s
>> generic/501 61s ... 63s
>> generic/502 1s ... 1s
>> generic/509 1s ... 1s
>> generic/510 1s ... 1s
>> generic/512 1s ... 1s
>> generic/520 16s ... 17s
>> generic/526 2s ... 1s
>> generic/527 0s ... 1s
>> generic/534 0s ... 1s
>> generic/535 2s ... 1s
>> generic/546 3s ... 3s
>> generic/547 2s ... 2s
>> generic/552 1s ... 1s
>> generic/557 1s ... 2s
>> generic/588 2s ... 1s
>> shared/002 9s ... 9s
>> xfs/011 18s ... 18s
>> xfs/029 1s ... 1s
>> xfs/051 18s ... 18s
>> xfs/057 23s ... 23s
>> xfs/079 14s ... 14s
>> xfs/095 1s ... 1s
>> xfs/119 3s ... 3s
>> xfs/121 6s ... 6s
>> xfs/141 14s ... 26s
>> xfs/181 14s ... 14s
>> xfs/216 3s ... 2s
>> xfs/217 2s ... 2s
>> xfs/439 [not run] test requires XFS bug_on_assert to be off, turn it off to run the test
>> Ran: generic/034 generic/039 generic/040 generic/041 generic/043 generic/044 generic/045 generic/046 generic/051 generic/052 generic/054 generic/055 generic/056 generic/057 generic/059 generic/065 generic/066 generic/073 generic/090 generic/101 generic/104 generic/106 generic/107 generic/177 generic/311 generic/321 generic/322 generic/325 generic/335 generic/336 generic/341 generic/342 generic/343 generic/376 generic/388 generic/417 generic/455 generic/457 generic/475 generic/479 generic/480 generic/481 generic/483 generic/489 generic/498 generic/501 generic/502 generic/509 generic/510 generic/512 generic/520 generic/526 generic/527 generic/534 generic/535 generic/546 generic/547 generic/552 generic/557 generic/588 shared/002 xfs/011 xfs/029 xfs/051 xfs/057 xfs/079 xfs/095 xfs/119 xfs/121 xfs/141 xfs/181 xfs/216 xfs/217 xfs/439
>> Not run: generic/455 generic/457 xfs/439
>> Passed all 74 tests
>>
>> These are the results of running ./check -g shutdown and ./check -g
>> log, respectively, on 5.11.0-xfstests-patched-next-20210301+ kernel
>> _with_ this patch applied on top:
>>
>> [email protected]:~/git/xfstests$ time sudo ./check -g shutdown 2>&1 | tee xfs-shutdown-patched.out
>> FSTYP -- xfs (debug)
>> PLATFORM -- Linux/x86_64 beefy 5.11.0-xfstests-patched-next-20210301+ #10 SMP Mon Mar 1 17:36:20 CST 2021
>> MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4
>> MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch
>>
>> generic/042 2s ... 3s
>> generic/043 13s ... 12s
>> generic/044 14s ... 15s
>> generic/045 18s ... 18s
>> generic/046 14s ... 15s
>> generic/047 21s ... 21s
>> generic/048 51s ... 51s
>> generic/049 9s ... 8s
>> generic/050 1s ... 2s
>> generic/051 76s ... 77s
>> generic/052 6s ... 2s
>> generic/054 35s ... 48s
>> generic/055 16s ... 17s
>> generic/388 77s ... 73s
>> generic/392 7s ... 5s
>> generic/417 13s ... 11s
>> generic/461 22s ... 21s
>> generic/468 2s ... 3s
>> generic/474 2s ... 1s
>> generic/475 90s ... 96s
>> generic/505 3s ... 3s
>> generic/506 1s ... 2s
>> generic/507 [not run] file system doesn't support chattr +AsSu
>> generic/508 2s ... 10s
>> generic/530 9s ... 13s
>> generic/536 2s ... 1s
>> generic/599 1s ... 1s
>> generic/622 24s ... 25s
>> xfs/051 18s ... 18s
>> xfs/079 14s ... 13s
>> xfs/121 6s ... 8s
>> xfs/181 11s ... 14s
>> xfs/212 2s ... 1s
>> Ran: generic/042 generic/043 generic/044 generic/045 generic/046 generic/047 generic/048 generic/049 generic/050 generic/051 generic/052 generic/054 generic/055 generic/388 generic/392 generic/417 generic/461 generic/468 generic/474 generic/475 generic/505 generic/506 generic/507 generic/508 generic/530 generic/536 generic/599 generic/622 xfs/051 xfs/079 xfs/121 xfs/181 xfs/212
>> Not run: generic/507
>> Passed all 33 tests
>>
>> [email protected]:~/git/xfstests$ time sudo ./check -g log 2>&1 | tee xfs-log-patched.out
>> FSTYP -- xfs (debug)
>> PLATFORM -- Linux/x86_64 beefy 5.11.0-xfstests-patched-next-20210301+ #10 SMP Mon Mar 1 17:36:20 CST 2021
>> MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4
>> MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch
>>
>> generic/034 1s ... 1s
>> generic/039 1s ... 1s
>> generic/040 5s ... 5s
>> generic/041 7s ... 7s
>> generic/043 12s ... 13s
>> generic/044 15s ... 15s
>> generic/045 18s ... 18s
>> generic/046 15s ... 14s
>> generic/051 77s ... 76s
>> generic/052 2s ... 1s
>> generic/054 48s ... 29s
>> generic/055 17s ... 16s
>> generic/056 1s ... 1s
>> generic/057 1s ... 1s
>> generic/059 2s ... 2s
>> generic/065 1s ... 1s
>> generic/066 1s ... 1s
>> generic/073 1s ... 1s
>> generic/090 1s ... 1s
>> generic/101 1s ... 1s
>> generic/104 1s ... 1s
>> generic/106 1s ... 1s
>> generic/107 1s ... 1s
>> generic/177 1s ... 1s
>> generic/311 68s ... 68s
>> generic/321 2s ... 2s
>> generic/322 1s ... 1s
>> generic/325 2s ... 1s
>> generic/335 1s ... 1s
>> generic/336 1s ... 1s
>> generic/341 1s ... 1s
>> generic/342 1s ... 1s
>> generic/343 1s ... 1s
>> generic/376 1s ... 1s
>> generic/388 73s ... 83s
>> generic/417 11s ... 11s
>> generic/455 [not run] This test requires a valid $LOGWRITES_DEV
>> generic/457 [not run] This test requires a valid $LOGWRITES_DEV
>> generic/475 96s ... 83s
>> generic/479 2s
>> generic/480 2s ... 1s
>> generic/481 0s ... 1s
>> generic/483 7s ... 7s
>> generic/489 1s ... 1s
>> generic/498 1s ... 1s
>> generic/501 63s ... 61s
>> generic/502 1s ... 1s
>> generic/509 1s ... 1s
>> generic/510 1s ... 1s
>> generic/512 1s ... 1s
>> generic/520 16s ... 16s
>> generic/526 1s ... 1s
>> generic/527 1s ... 1s
>> generic/534 1s ... 1s
>> generic/535 1s ... 1s
>> generic/546 4s ... 4s
>> generic/547 2s ... 2s
>> generic/552 1s ... 1s
>> generic/557 1s ... 1s
>> generic/588 2s ... 1s
>> shared/002 8s ... 9s
>> xfs/011 18s ... 18s
>> xfs/029 1s ... 1s
>> xfs/051 18s ... 18s
>> xfs/057 23s ... 24s
>> xfs/079 13s ... 14s
>> xfs/095 2s ... 1s
>> xfs/119 3s ... 3s
>> xfs/121 8s ... 6s
>> xfs/141 18s ... 12s
>> xfs/181 14s ... 12s
>> xfs/216 3s ... 2s
>> xfs/217 2s ... 2s
>> xfs/439 [not run] test requires XFS bug_on_assert to be off, turn it off to run the test
>> Ran: generic/034 generic/039 generic/040 generic/041 generic/043 generic/044 generic/045 generic/046 generic/051 generic/052 generic/054 generic/055 generic/056 generic/057 generic/059 generic/065 generic/066 generic/073 generic/090 generic/101 generic/104 generic/106 generic/107 generic/177 generic/311 generic/321 generic/322 generic/325 generic/335 generic/336 generic/341 generic/342 generic/343 generic/376 generic/388 generic/417 generic/455 generic/457 generic/475 generic/479 generic/480 generic/481 generic/483 generic/489 generic/498 generic/501 generic/502 generic/509 generic/510 generic/512 generic/520 generic/526 generic/527 generic/534 generic/535 generic/546 generic/547 generic/552 generic/557 generic/588 shared/002 xfs/011 xfs/029 xfs/051 xfs/057 xfs/079 xfs/095 xfs/119 xfs/121 xfs/141 xfs/181 xfs/216 xfs/217 xfs/439
>> Not run: generic/455 generic/457 xfs/439
>> Passed all 74 tests
>>
>> Notice that the test results before and after this patch is applied are
>> identical and successful. Other tests might need to be run in order to
>> verify everything is working as expected. For such tests, the intervention
>> of the maintainers might be needed.
>>
>> [1] https://en.wikipedia.org/wiki/Flexible_array_member
>> [2] https://www.kernel.org/doc/html/v5.9/process/deprecated.html#zero-length-and-one-element-arrays
>>
>> Link: https://github.com/KSPP/linux/issues/79
>> Build-tested-by: kernel test robot <[email protected]>
>> Link: https://lore.kernel.org/lkml/603e3177.WsvTXRpcLn5wdYW6%[email protected]/
>> Signed-off-by: Gustavo A. R. Silva <[email protected]>
>> ---
>> fs/xfs/libxfs/xfs_log_format.h | 12 +++++------
>> fs/xfs/xfs_extfree_item.c | 39 +++++++++++++++-------------------
>> fs/xfs/xfs_ondisk.h | 8 +++----
>> 3 files changed, 27 insertions(+), 32 deletions(-)
>>
>> diff --git a/fs/xfs/libxfs/xfs_log_format.h b/fs/xfs/libxfs/xfs_log_format.h
>> index 8bd00da6d2a4..9934a465b441 100644
>> --- a/fs/xfs/libxfs/xfs_log_format.h
>> +++ b/fs/xfs/libxfs/xfs_log_format.h
>> @@ -574,7 +574,7 @@ typedef struct xfs_efi_log_format {
>> uint16_t efi_size; /* size of this item */
>> uint32_t efi_nextents; /* # extents to free */
>> uint64_t efi_id; /* efi identifier */
>> - xfs_extent_t efi_extents[1]; /* array of extents to free */
>> + xfs_extent_t efi_extents[]; /* array of extents to free */
>> } xfs_efi_log_format_t;
>>
>> typedef struct xfs_efi_log_format_32 {
>> @@ -582,7 +582,7 @@ typedef struct xfs_efi_log_format_32 {
>> uint16_t efi_size; /* size of this item */
>> uint32_t efi_nextents; /* # extents to free */
>> uint64_t efi_id; /* efi identifier */
>> - xfs_extent_32_t efi_extents[1]; /* array of extents to free */
>> + xfs_extent_32_t efi_extents[]; /* array of extents to free */
>> } __attribute__((packed)) xfs_efi_log_format_32_t;
>>
>> typedef struct xfs_efi_log_format_64 {
>> @@ -590,7 +590,7 @@ typedef struct xfs_efi_log_format_64 {
>> uint16_t efi_size; /* size of this item */
>> uint32_t efi_nextents; /* # extents to free */
>> uint64_t efi_id; /* efi identifier */
>> - xfs_extent_64_t efi_extents[1]; /* array of extents to free */
>> + xfs_extent_64_t efi_extents[]; /* array of extents to free */
>> } xfs_efi_log_format_64_t;
>>
>> /*
>> @@ -603,7 +603,7 @@ typedef struct xfs_efd_log_format {
>> uint16_t efd_size; /* size of this item */
>> uint32_t efd_nextents; /* # of extents freed */
>> uint64_t efd_efi_id; /* id of corresponding efi */
>> - xfs_extent_t efd_extents[1]; /* array of extents freed */
>> + xfs_extent_t efd_extents[]; /* array of extents freed */
>> } xfs_efd_log_format_t;
>>
>> typedef struct xfs_efd_log_format_32 {
>> @@ -611,7 +611,7 @@ typedef struct xfs_efd_log_format_32 {
>> uint16_t efd_size; /* size of this item */
>> uint32_t efd_nextents; /* # of extents freed */
>> uint64_t efd_efi_id; /* id of corresponding efi */
>> - xfs_extent_32_t efd_extents[1]; /* array of extents freed */
>> + xfs_extent_32_t efd_extents[]; /* array of extents freed */
>> } __attribute__((packed)) xfs_efd_log_format_32_t;
>>
>> typedef struct xfs_efd_log_format_64 {
>> @@ -619,7 +619,7 @@ typedef struct xfs_efd_log_format_64 {
>> uint16_t efd_size; /* size of this item */
>> uint32_t efd_nextents; /* # of extents freed */
>> uint64_t efd_efi_id; /* id of corresponding efi */
>> - xfs_extent_64_t efd_extents[1]; /* array of extents freed */
>> + xfs_extent_64_t efd_extents[]; /* array of extents freed */
>> } xfs_efd_log_format_64_t;
>>
>> /*
>> diff --git a/fs/xfs/xfs_extfree_item.c b/fs/xfs/xfs_extfree_item.c
>> index 93223ebb3372..5ed3ea93071c 100644
>> --- a/fs/xfs/xfs_extfree_item.c
>> +++ b/fs/xfs/xfs_extfree_item.c
>> @@ -73,8 +73,8 @@ static inline int
>> xfs_efi_item_sizeof(
>> struct xfs_efi_log_item *efip)
>> {
>> - return sizeof(struct xfs_efi_log_format) +
>> - (efip->efi_format.efi_nextents - 1) * sizeof(xfs_extent_t);
>> + return struct_size(&efip->efi_format, efi_extents,
>> + efip->efi_format.efi_nextents);
>> }
>>
>> STATIC void
>> @@ -153,17 +153,14 @@ xfs_efi_init(
>>
>> {
>> struct xfs_efi_log_item *efip;
>> - uint size;
>>
>> ASSERT(nextents > 0);
>> - if (nextents > XFS_EFI_MAX_FAST_EXTENTS) {
>> - size = (uint)(sizeof(struct xfs_efi_log_item) +
>> - ((nextents - 1) * sizeof(xfs_extent_t)));
>> - efip = kmem_zalloc(size, 0);
>> - } else {
>> + if (nextents > XFS_EFI_MAX_FAST_EXTENTS)
>> + efip = kmem_zalloc(struct_size(efip, efi_format.efi_extents,
>> + nextents), 0);
>> + else
>> efip = kmem_cache_zalloc(xfs_efi_zone,
>> GFP_KERNEL | __GFP_NOFAIL);
>> - }
>>
>> xfs_log_item_init(mp, &efip->efi_item, XFS_LI_EFI, &xfs_efi_item_ops);
>> efip->efi_format.efi_nextents = nextents;
>> @@ -186,12 +183,12 @@ xfs_efi_copy_format(xfs_log_iovec_t *buf, xfs_efi_log_format_t *dst_efi_fmt)
>> {
>> xfs_efi_log_format_t *src_efi_fmt = buf->i_addr;
>> uint i;
>> - uint len = sizeof(xfs_efi_log_format_t) +
>> - (src_efi_fmt->efi_nextents - 1) * sizeof(xfs_extent_t);
>> + size_t len = struct_size(src_efi_fmt, efi_extents,
>> + src_efi_fmt->efi_nextents);
>> uint len32 = sizeof(xfs_efi_log_format_32_t) +
>> - (src_efi_fmt->efi_nextents - 1) * sizeof(xfs_extent_32_t);
>> + src_efi_fmt->efi_nextents * sizeof(xfs_extent_32_t);
>
> Shouldn't these be converted to struct_size() too?
>
> It seems to work all right for casted NULL pointers, and then we get all
> the typechecking and multiplication overflow checking, e.g.:
>
> size_t len64 = struct_size((struct xfs_efi_log_format_32 *)NULL,
> efi_extents src_efi_fmt->efi_nextents);

Yeah; in that case, what do you think about casting 0, instead of NULL:

uint len32 = struct_size((xfs_efi_log_format_32_t *)0, efi_extents,
src_efi_fmt->efi_nextents);
uint len64 = struct_size((xfs_efi_log_format_64_t *)0, efi_extents,
src_efi_fmt->efi_nextents);

Thanks
--
Gustavo

>
> --D
>
>> uint len64 = sizeof(xfs_efi_log_format_64_t) +
>> - (src_efi_fmt->efi_nextents - 1) * sizeof(xfs_extent_64_t);
>> + src_efi_fmt->efi_nextents * sizeof(xfs_extent_64_t);
>>
>> if (buf->i_len == len) {
>> memcpy((char *)dst_efi_fmt, (char*)src_efi_fmt, len);
>> @@ -254,7 +251,7 @@ xfs_efd_item_sizeof(
>> struct xfs_efd_log_item *efdp)
>> {
>> return sizeof(xfs_efd_log_format_t) +
>> - (efdp->efd_format.efd_nextents - 1) * sizeof(xfs_extent_t);
>> + efdp->efd_format.efd_nextents * sizeof(xfs_extent_t);
>> }
>>
>> STATIC void
>> @@ -328,14 +325,12 @@ xfs_trans_get_efd(
>>
>> ASSERT(nextents > 0);
>>
>> - if (nextents > XFS_EFD_MAX_FAST_EXTENTS) {
>> - efdp = kmem_zalloc(sizeof(struct xfs_efd_log_item) +
>> - (nextents - 1) * sizeof(struct xfs_extent),
>> - 0);
>> - } else {
>> + if (nextents > XFS_EFD_MAX_FAST_EXTENTS)
>> + efdp = kmem_zalloc(struct_size(efip, efi_format.efi_extents,
>> + nextents), 0);
>> + else
>> efdp = kmem_cache_zalloc(xfs_efd_zone,
>> GFP_KERNEL | __GFP_NOFAIL);
>> - }
>>
>> xfs_log_item_init(tp->t_mountp, &efdp->efd_item, XFS_LI_EFD,
>> &xfs_efd_item_ops);
>> @@ -747,9 +742,9 @@ xlog_recover_efd_commit_pass2(
>>
>> efd_formatp = item->ri_buf[0].i_addr;
>> ASSERT((item->ri_buf[0].i_len == (sizeof(xfs_efd_log_format_32_t) +
>> - ((efd_formatp->efd_nextents - 1) * sizeof(xfs_extent_32_t)))) ||
>> + (efd_formatp->efd_nextents * sizeof(xfs_extent_32_t)))) ||
>> (item->ri_buf[0].i_len == (sizeof(xfs_efd_log_format_64_t) +
>> - ((efd_formatp->efd_nextents - 1) * sizeof(xfs_extent_64_t)))));
>> + (efd_formatp->efd_nextents * sizeof(xfs_extent_64_t)))));
>>
>> xlog_recover_release_intent(log, XFS_LI_EFI, efd_formatp->efd_efi_id);
>> return 0;
>> diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
>> index 0aa87c210104..f58e0510385a 100644
>> --- a/fs/xfs/xfs_ondisk.h
>> +++ b/fs/xfs/xfs_ondisk.h
>> @@ -118,10 +118,10 @@ xfs_check_ondisk_structs(void)
>> /* log structures */
>> XFS_CHECK_STRUCT_SIZE(struct xfs_buf_log_format, 88);
>> XFS_CHECK_STRUCT_SIZE(struct xfs_dq_logformat, 24);
>> - XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_32, 28);
>> - XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_64, 32);
>> - XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_32, 28);
>> - XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_64, 32);
>> + XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_32, 16);
>> + XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_64, 16);
>> + XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_32, 16);
>> + XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_64, 16);
>> XFS_CHECK_STRUCT_SIZE(struct xfs_extent_32, 12);
>> XFS_CHECK_STRUCT_SIZE(struct xfs_extent_64, 16);
>> XFS_CHECK_STRUCT_SIZE(struct xfs_log_dinode, 176);
>> --
>> 2.27.0
>>

2021-03-09 21:28:35

by Darrick J. Wong

[permalink] [raw]
Subject: Re: [PATCH][next] xfs: Replace one-element arrays with flexible-array members

On Tue, Mar 09, 2021 at 01:57:36PM -0600, Gustavo A. R. Silva wrote:
> Hi Darrick,
>
> Please, see my comments below...
>
> On 3/9/21 11:42, Darrick J. Wong wrote:
> > On Tue, Mar 02, 2021 at 09:05:58AM -0600, Gustavo A. R. Silva wrote:
> >> There is a regular need in the kernel to provide a way to declare having
> >> a dynamically sized set of trailing elements in a structure. Kernel code
> >> should always use “flexible array members”[1] for these cases. The older
> >> style of one-element or zero-length arrays should no longer be used[2].
> >>
> >> Refactor the code according to the use of flexible-array members in
> >> multiple structures, instead of one-element arrays. Also, make use of
> >> the new struct_size() helper to properly calculate the size of multiple
> >> structures that contain flexible-array members.
> >>
> >> Below are the results of running xfstests for groups shutdown and log
> >> with the following configuration in local.config:
> >>
> >> export TEST_DEV=/dev/sda3
> >> export TEST_DIR=/mnt/test
> >> export SCRATCH_DEV=/dev/sda4
> >> export SCRATCH_MNT=/mnt/scratch
> >>
> >> The size for both partitions /dev/sda3 and /dev/sda4 is 25GB.
> >>
> >> These are the results of running ./check -g shutdown and ./check -g
> >> log, respectively, on 5.11.0-next-20210301 kernel _without_ this patch
> >> applied:
> >>
> >> [email protected]:~/git/xfstests$ time sudo ./check -g shutdown 2>&1 | tee xfs-shutdown-no-patch.out
> >> FSTYP -- xfs (debug)
> >> PLATFORM -- Linux/x86_64 beefy 5.11.0-next-20210301 #4 SMP Mon Mar 1 05:42:06 CST 2021
> >> MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4
> >> MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch
> >>
> >> generic/042 2s ... 2s
> >> generic/043 13s ... 13s
> >> generic/044 14s ... 14s
> >> generic/045 18s ... 18s
> >> generic/046 14s ... 14s
> >> generic/047 20s ... 22s
> >> generic/048 51s ... 50s
> >> generic/049 9s ... 8s
> >> generic/050 2s ... 1s
> >> generic/051 76s ... 75s
> >> generic/052 1s ... 2s
> >> generic/054 31s ... 30s
> >> generic/055 16s ... 21s
> >> generic/388 89s ... 75s
> >> generic/392 5s ... 5s
> >> generic/417 11s ... 11s
> >> generic/461 21s ... 22s
> >> generic/468 3s ... 3s
> >> generic/474 1s ... 1s
> >> generic/475 86s ... 93s
> >> generic/505 2s ... 2s
> >> generic/506 2s ... 2s
> >> generic/507 [not run] file system doesn't support chattr +AsSu
> >> generic/508 1s ... 1s
> >> generic/530 10s ... 10s
> >> generic/536 3s ... 2s
> >> generic/599 1s ... 1s
> >> generic/622 23s ... 24s
> >> xfs/051 18s ... 18s
> >> xfs/079 15s ... 14s
> >> xfs/121 6s ... 16s
> >> xfs/181 12s ... 15s
> >> xfs/212 1s ... 3s
> >> Ran: generic/042 generic/043 generic/044 generic/045 generic/046 generic/047 generic/048 generic/049 generic/050 generic/051 generic/052 generic/054 generic/055 generic/388 generic/392 generic/417 generic/461 generic/468 generic/474 generic/475 generic/505 generic/506 generic/507 generic/508 generic/530 generic/536 generic/599 generic/622 xfs/051 xfs/079 xfs/121 xfs/181 xfs/212
> >> Not run: generic/507
> >> Passed all 33 tests
> >>
> >> [email protected]:~/git/xfstests$ time sudo ./check -g log 2>&1 | tee xfs-log-no-patch.out
> >> FSTYP -- xfs (debug)
> >> PLATFORM -- Linux/x86_64 beefy 5.11.0-next-20210301 #4 SMP Mon Mar 1 05:42:06 CST 2021
> >> MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4
> >> MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch
> >>
> >> generic/034 1s ... 1s
> >> generic/039 1s ... 1s
> >> generic/040 5s ... 5s
> >> generic/041 7s ... 7s
> >> generic/043 13s ... 13s
> >> generic/044 14s ... 14s
> >> generic/045 18s ... 18s
> >> generic/046 14s ... 14s
> >> generic/051 76s ... 76s
> >> generic/052 1s ... 2s
> >> generic/054 30s ... 48s
> >> generic/055 23s ... 15s
> >> generic/056 1s ... 1s
> >> generic/057 1s ... 1s
> >> generic/059 2s ... 2s
> >> generic/065 1s ... 1s
> >> generic/066 1s ... 2s
> >> generic/073 1s ... 1s
> >> generic/090 1s ... 1s
> >> generic/101 1s ... 1s
> >> generic/104 1s ... 1s
> >> generic/106 1s ... 1s
> >> generic/107 1s ... 1s
> >> generic/177 1s ... 1s
> >> generic/311 67s ... 67s
> >> generic/321 2s ... 2s
> >> generic/322 1s ... 2s
> >> generic/325 1s ... 1s
> >> generic/335 1s ... 1s
> >> generic/336 2s ... 1s
> >> generic/341 1s ... 1s
> >> generic/342 1s ... 1s
> >> generic/343 1s ... 1s
> >> generic/376 1s ... 1s
> >> generic/388 75s ... 97s
> >> generic/417 15s ... 12s
> >> generic/455 [not run] This test requires a valid $LOGWRITES_DEV
> >> generic/457 [not run] This test requires a valid $LOGWRITES_DEV
> >> generic/475 88s ... 89s
> >> generic/479 2s ... 2s
> >> generic/480 1s ... 1s
> >> generic/481 1s ... 1s
> >> generic/483 7s ... 6s
> >> generic/489 1s ... 1s
> >> generic/498 1s ... 1s
> >> generic/501 61s ... 63s
> >> generic/502 1s ... 1s
> >> generic/509 1s ... 1s
> >> generic/510 1s ... 1s
> >> generic/512 1s ... 1s
> >> generic/520 16s ... 17s
> >> generic/526 2s ... 1s
> >> generic/527 0s ... 1s
> >> generic/534 0s ... 1s
> >> generic/535 2s ... 1s
> >> generic/546 3s ... 3s
> >> generic/547 2s ... 2s
> >> generic/552 1s ... 1s
> >> generic/557 1s ... 2s
> >> generic/588 2s ... 1s
> >> shared/002 9s ... 9s
> >> xfs/011 18s ... 18s
> >> xfs/029 1s ... 1s
> >> xfs/051 18s ... 18s
> >> xfs/057 23s ... 23s
> >> xfs/079 14s ... 14s
> >> xfs/095 1s ... 1s
> >> xfs/119 3s ... 3s
> >> xfs/121 6s ... 6s
> >> xfs/141 14s ... 26s
> >> xfs/181 14s ... 14s
> >> xfs/216 3s ... 2s
> >> xfs/217 2s ... 2s
> >> xfs/439 [not run] test requires XFS bug_on_assert to be off, turn it off to run the test
> >> Ran: generic/034 generic/039 generic/040 generic/041 generic/043 generic/044 generic/045 generic/046 generic/051 generic/052 generic/054 generic/055 generic/056 generic/057 generic/059 generic/065 generic/066 generic/073 generic/090 generic/101 generic/104 generic/106 generic/107 generic/177 generic/311 generic/321 generic/322 generic/325 generic/335 generic/336 generic/341 generic/342 generic/343 generic/376 generic/388 generic/417 generic/455 generic/457 generic/475 generic/479 generic/480 generic/481 generic/483 generic/489 generic/498 generic/501 generic/502 generic/509 generic/510 generic/512 generic/520 generic/526 generic/527 generic/534 generic/535 generic/546 generic/547 generic/552 generic/557 generic/588 shared/002 xfs/011 xfs/029 xfs/051 xfs/057 xfs/079 xfs/095 xfs/119 xfs/121 xfs/141 xfs/181 xfs/216 xfs/217 xfs/439
> >> Not run: generic/455 generic/457 xfs/439
> >> Passed all 74 tests
> >>
> >> These are the results of running ./check -g shutdown and ./check -g
> >> log, respectively, on 5.11.0-xfstests-patched-next-20210301+ kernel
> >> _with_ this patch applied on top:
> >>
> >> [email protected]:~/git/xfstests$ time sudo ./check -g shutdown 2>&1 | tee xfs-shutdown-patched.out
> >> FSTYP -- xfs (debug)
> >> PLATFORM -- Linux/x86_64 beefy 5.11.0-xfstests-patched-next-20210301+ #10 SMP Mon Mar 1 17:36:20 CST 2021
> >> MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4
> >> MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch
> >>
> >> generic/042 2s ... 3s
> >> generic/043 13s ... 12s
> >> generic/044 14s ... 15s
> >> generic/045 18s ... 18s
> >> generic/046 14s ... 15s
> >> generic/047 21s ... 21s
> >> generic/048 51s ... 51s
> >> generic/049 9s ... 8s
> >> generic/050 1s ... 2s
> >> generic/051 76s ... 77s
> >> generic/052 6s ... 2s
> >> generic/054 35s ... 48s
> >> generic/055 16s ... 17s
> >> generic/388 77s ... 73s
> >> generic/392 7s ... 5s
> >> generic/417 13s ... 11s
> >> generic/461 22s ... 21s
> >> generic/468 2s ... 3s
> >> generic/474 2s ... 1s
> >> generic/475 90s ... 96s
> >> generic/505 3s ... 3s
> >> generic/506 1s ... 2s
> >> generic/507 [not run] file system doesn't support chattr +AsSu
> >> generic/508 2s ... 10s
> >> generic/530 9s ... 13s
> >> generic/536 2s ... 1s
> >> generic/599 1s ... 1s
> >> generic/622 24s ... 25s
> >> xfs/051 18s ... 18s
> >> xfs/079 14s ... 13s
> >> xfs/121 6s ... 8s
> >> xfs/181 11s ... 14s
> >> xfs/212 2s ... 1s
> >> Ran: generic/042 generic/043 generic/044 generic/045 generic/046 generic/047 generic/048 generic/049 generic/050 generic/051 generic/052 generic/054 generic/055 generic/388 generic/392 generic/417 generic/461 generic/468 generic/474 generic/475 generic/505 generic/506 generic/507 generic/508 generic/530 generic/536 generic/599 generic/622 xfs/051 xfs/079 xfs/121 xfs/181 xfs/212
> >> Not run: generic/507
> >> Passed all 33 tests
> >>
> >> [email protected]:~/git/xfstests$ time sudo ./check -g log 2>&1 | tee xfs-log-patched.out
> >> FSTYP -- xfs (debug)
> >> PLATFORM -- Linux/x86_64 beefy 5.11.0-xfstests-patched-next-20210301+ #10 SMP Mon Mar 1 17:36:20 CST 2021
> >> MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4
> >> MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch
> >>
> >> generic/034 1s ... 1s
> >> generic/039 1s ... 1s
> >> generic/040 5s ... 5s
> >> generic/041 7s ... 7s
> >> generic/043 12s ... 13s
> >> generic/044 15s ... 15s
> >> generic/045 18s ... 18s
> >> generic/046 15s ... 14s
> >> generic/051 77s ... 76s
> >> generic/052 2s ... 1s
> >> generic/054 48s ... 29s
> >> generic/055 17s ... 16s
> >> generic/056 1s ... 1s
> >> generic/057 1s ... 1s
> >> generic/059 2s ... 2s
> >> generic/065 1s ... 1s
> >> generic/066 1s ... 1s
> >> generic/073 1s ... 1s
> >> generic/090 1s ... 1s
> >> generic/101 1s ... 1s
> >> generic/104 1s ... 1s
> >> generic/106 1s ... 1s
> >> generic/107 1s ... 1s
> >> generic/177 1s ... 1s
> >> generic/311 68s ... 68s
> >> generic/321 2s ... 2s
> >> generic/322 1s ... 1s
> >> generic/325 2s ... 1s
> >> generic/335 1s ... 1s
> >> generic/336 1s ... 1s
> >> generic/341 1s ... 1s
> >> generic/342 1s ... 1s
> >> generic/343 1s ... 1s
> >> generic/376 1s ... 1s
> >> generic/388 73s ... 83s
> >> generic/417 11s ... 11s
> >> generic/455 [not run] This test requires a valid $LOGWRITES_DEV
> >> generic/457 [not run] This test requires a valid $LOGWRITES_DEV
> >> generic/475 96s ... 83s
> >> generic/479 2s
> >> generic/480 2s ... 1s
> >> generic/481 0s ... 1s
> >> generic/483 7s ... 7s
> >> generic/489 1s ... 1s
> >> generic/498 1s ... 1s
> >> generic/501 63s ... 61s
> >> generic/502 1s ... 1s
> >> generic/509 1s ... 1s
> >> generic/510 1s ... 1s
> >> generic/512 1s ... 1s
> >> generic/520 16s ... 16s
> >> generic/526 1s ... 1s
> >> generic/527 1s ... 1s
> >> generic/534 1s ... 1s
> >> generic/535 1s ... 1s
> >> generic/546 4s ... 4s
> >> generic/547 2s ... 2s
> >> generic/552 1s ... 1s
> >> generic/557 1s ... 1s
> >> generic/588 2s ... 1s
> >> shared/002 8s ... 9s
> >> xfs/011 18s ... 18s
> >> xfs/029 1s ... 1s
> >> xfs/051 18s ... 18s
> >> xfs/057 23s ... 24s
> >> xfs/079 13s ... 14s
> >> xfs/095 2s ... 1s
> >> xfs/119 3s ... 3s
> >> xfs/121 8s ... 6s
> >> xfs/141 18s ... 12s
> >> xfs/181 14s ... 12s
> >> xfs/216 3s ... 2s
> >> xfs/217 2s ... 2s
> >> xfs/439 [not run] test requires XFS bug_on_assert to be off, turn it off to run the test
> >> Ran: generic/034 generic/039 generic/040 generic/041 generic/043 generic/044 generic/045 generic/046 generic/051 generic/052 generic/054 generic/055 generic/056 generic/057 generic/059 generic/065 generic/066 generic/073 generic/090 generic/101 generic/104 generic/106 generic/107 generic/177 generic/311 generic/321 generic/322 generic/325 generic/335 generic/336 generic/341 generic/342 generic/343 generic/376 generic/388 generic/417 generic/455 generic/457 generic/475 generic/479 generic/480 generic/481 generic/483 generic/489 generic/498 generic/501 generic/502 generic/509 generic/510 generic/512 generic/520 generic/526 generic/527 generic/534 generic/535 generic/546 generic/547 generic/552 generic/557 generic/588 shared/002 xfs/011 xfs/029 xfs/051 xfs/057 xfs/079 xfs/095 xfs/119 xfs/121 xfs/141 xfs/181 xfs/216 xfs/217 xfs/439
> >> Not run: generic/455 generic/457 xfs/439
> >> Passed all 74 tests
> >>
> >> Notice that the test results before and after this patch is applied are
> >> identical and successful. Other tests might need to be run in order to
> >> verify everything is working as expected. For such tests, the intervention
> >> of the maintainers might be needed.
> >>
> >> [1] https://en.wikipedia.org/wiki/Flexible_array_member
> >> [2] https://www.kernel.org/doc/html/v5.9/process/deprecated.html#zero-length-and-one-element-arrays
> >>
> >> Link: https://github.com/KSPP/linux/issues/79
> >> Build-tested-by: kernel test robot <[email protected]>
> >> Link: https://lore.kernel.org/lkml/603e3177.WsvTXRpcLn5wdYW6%[email protected]/
> >> Signed-off-by: Gustavo A. R. Silva <[email protected]>
> >> ---
> >> fs/xfs/libxfs/xfs_log_format.h | 12 +++++------
> >> fs/xfs/xfs_extfree_item.c | 39 +++++++++++++++-------------------
> >> fs/xfs/xfs_ondisk.h | 8 +++----
> >> 3 files changed, 27 insertions(+), 32 deletions(-)
> >>
> >> diff --git a/fs/xfs/libxfs/xfs_log_format.h b/fs/xfs/libxfs/xfs_log_format.h
> >> index 8bd00da6d2a4..9934a465b441 100644
> >> --- a/fs/xfs/libxfs/xfs_log_format.h
> >> +++ b/fs/xfs/libxfs/xfs_log_format.h
> >> @@ -574,7 +574,7 @@ typedef struct xfs_efi_log_format {
> >> uint16_t efi_size; /* size of this item */
> >> uint32_t efi_nextents; /* # extents to free */
> >> uint64_t efi_id; /* efi identifier */
> >> - xfs_extent_t efi_extents[1]; /* array of extents to free */
> >> + xfs_extent_t efi_extents[]; /* array of extents to free */
> >> } xfs_efi_log_format_t;
> >>
> >> typedef struct xfs_efi_log_format_32 {
> >> @@ -582,7 +582,7 @@ typedef struct xfs_efi_log_format_32 {
> >> uint16_t efi_size; /* size of this item */
> >> uint32_t efi_nextents; /* # extents to free */
> >> uint64_t efi_id; /* efi identifier */
> >> - xfs_extent_32_t efi_extents[1]; /* array of extents to free */
> >> + xfs_extent_32_t efi_extents[]; /* array of extents to free */
> >> } __attribute__((packed)) xfs_efi_log_format_32_t;
> >>
> >> typedef struct xfs_efi_log_format_64 {
> >> @@ -590,7 +590,7 @@ typedef struct xfs_efi_log_format_64 {
> >> uint16_t efi_size; /* size of this item */
> >> uint32_t efi_nextents; /* # extents to free */
> >> uint64_t efi_id; /* efi identifier */
> >> - xfs_extent_64_t efi_extents[1]; /* array of extents to free */
> >> + xfs_extent_64_t efi_extents[]; /* array of extents to free */
> >> } xfs_efi_log_format_64_t;
> >>
> >> /*
> >> @@ -603,7 +603,7 @@ typedef struct xfs_efd_log_format {
> >> uint16_t efd_size; /* size of this item */
> >> uint32_t efd_nextents; /* # of extents freed */
> >> uint64_t efd_efi_id; /* id of corresponding efi */
> >> - xfs_extent_t efd_extents[1]; /* array of extents freed */
> >> + xfs_extent_t efd_extents[]; /* array of extents freed */
> >> } xfs_efd_log_format_t;
> >>
> >> typedef struct xfs_efd_log_format_32 {
> >> @@ -611,7 +611,7 @@ typedef struct xfs_efd_log_format_32 {
> >> uint16_t efd_size; /* size of this item */
> >> uint32_t efd_nextents; /* # of extents freed */
> >> uint64_t efd_efi_id; /* id of corresponding efi */
> >> - xfs_extent_32_t efd_extents[1]; /* array of extents freed */
> >> + xfs_extent_32_t efd_extents[]; /* array of extents freed */
> >> } __attribute__((packed)) xfs_efd_log_format_32_t;
> >>
> >> typedef struct xfs_efd_log_format_64 {
> >> @@ -619,7 +619,7 @@ typedef struct xfs_efd_log_format_64 {
> >> uint16_t efd_size; /* size of this item */
> >> uint32_t efd_nextents; /* # of extents freed */
> >> uint64_t efd_efi_id; /* id of corresponding efi */
> >> - xfs_extent_64_t efd_extents[1]; /* array of extents freed */
> >> + xfs_extent_64_t efd_extents[]; /* array of extents freed */
> >> } xfs_efd_log_format_64_t;
> >>
> >> /*
> >> diff --git a/fs/xfs/xfs_extfree_item.c b/fs/xfs/xfs_extfree_item.c
> >> index 93223ebb3372..5ed3ea93071c 100644
> >> --- a/fs/xfs/xfs_extfree_item.c
> >> +++ b/fs/xfs/xfs_extfree_item.c
> >> @@ -73,8 +73,8 @@ static inline int
> >> xfs_efi_item_sizeof(
> >> struct xfs_efi_log_item *efip)
> >> {
> >> - return sizeof(struct xfs_efi_log_format) +
> >> - (efip->efi_format.efi_nextents - 1) * sizeof(xfs_extent_t);
> >> + return struct_size(&efip->efi_format, efi_extents,
> >> + efip->efi_format.efi_nextents);
> >> }
> >>
> >> STATIC void
> >> @@ -153,17 +153,14 @@ xfs_efi_init(
> >>
> >> {
> >> struct xfs_efi_log_item *efip;
> >> - uint size;
> >>
> >> ASSERT(nextents > 0);
> >> - if (nextents > XFS_EFI_MAX_FAST_EXTENTS) {
> >> - size = (uint)(sizeof(struct xfs_efi_log_item) +
> >> - ((nextents - 1) * sizeof(xfs_extent_t)));
> >> - efip = kmem_zalloc(size, 0);
> >> - } else {
> >> + if (nextents > XFS_EFI_MAX_FAST_EXTENTS)
> >> + efip = kmem_zalloc(struct_size(efip, efi_format.efi_extents,
> >> + nextents), 0);
> >> + else
> >> efip = kmem_cache_zalloc(xfs_efi_zone,
> >> GFP_KERNEL | __GFP_NOFAIL);
> >> - }
> >>
> >> xfs_log_item_init(mp, &efip->efi_item, XFS_LI_EFI, &xfs_efi_item_ops);
> >> efip->efi_format.efi_nextents = nextents;
> >> @@ -186,12 +183,12 @@ xfs_efi_copy_format(xfs_log_iovec_t *buf, xfs_efi_log_format_t *dst_efi_fmt)
> >> {
> >> xfs_efi_log_format_t *src_efi_fmt = buf->i_addr;
> >> uint i;
> >> - uint len = sizeof(xfs_efi_log_format_t) +
> >> - (src_efi_fmt->efi_nextents - 1) * sizeof(xfs_extent_t);
> >> + size_t len = struct_size(src_efi_fmt, efi_extents,
> >> + src_efi_fmt->efi_nextents);
> >> uint len32 = sizeof(xfs_efi_log_format_32_t) +
> >> - (src_efi_fmt->efi_nextents - 1) * sizeof(xfs_extent_32_t);
> >> + src_efi_fmt->efi_nextents * sizeof(xfs_extent_32_t);
> >
> > Shouldn't these be converted to struct_size() too?
> >
> > It seems to work all right for casted NULL pointers, and then we get all
> > the typechecking and multiplication overflow checking, e.g.:
> >
> > size_t len64 = struct_size((struct xfs_efi_log_format_32 *)NULL,
> > efi_extents src_efi_fmt->efi_nextents);
>
> Yeah; in that case, what do you think about casting 0, instead of NULL:
>
> uint len32 = struct_size((xfs_efi_log_format_32_t *)0, efi_extents,
> src_efi_fmt->efi_nextents);
> uint len64 = struct_size((xfs_efi_log_format_64_t *)0, efi_extents,
> src_efi_fmt->efi_nextents);

I don't have a preference either way, either here or for the half-dozen
more of these scattered elsewhere in the file.

--D

> Thanks
> --
> Gustavo
>
> >
> > --D
> >
> >> uint len64 = sizeof(xfs_efi_log_format_64_t) +
> >> - (src_efi_fmt->efi_nextents - 1) * sizeof(xfs_extent_64_t);
> >> + src_efi_fmt->efi_nextents * sizeof(xfs_extent_64_t);
> >>
> >> if (buf->i_len == len) {
> >> memcpy((char *)dst_efi_fmt, (char*)src_efi_fmt, len);
> >> @@ -254,7 +251,7 @@ xfs_efd_item_sizeof(
> >> struct xfs_efd_log_item *efdp)
> >> {
> >> return sizeof(xfs_efd_log_format_t) +
> >> - (efdp->efd_format.efd_nextents - 1) * sizeof(xfs_extent_t);
> >> + efdp->efd_format.efd_nextents * sizeof(xfs_extent_t);
> >> }
> >>
> >> STATIC void
> >> @@ -328,14 +325,12 @@ xfs_trans_get_efd(
> >>
> >> ASSERT(nextents > 0);
> >>
> >> - if (nextents > XFS_EFD_MAX_FAST_EXTENTS) {
> >> - efdp = kmem_zalloc(sizeof(struct xfs_efd_log_item) +
> >> - (nextents - 1) * sizeof(struct xfs_extent),
> >> - 0);
> >> - } else {
> >> + if (nextents > XFS_EFD_MAX_FAST_EXTENTS)
> >> + efdp = kmem_zalloc(struct_size(efip, efi_format.efi_extents,
> >> + nextents), 0);
> >> + else
> >> efdp = kmem_cache_zalloc(xfs_efd_zone,
> >> GFP_KERNEL | __GFP_NOFAIL);
> >> - }
> >>
> >> xfs_log_item_init(tp->t_mountp, &efdp->efd_item, XFS_LI_EFD,
> >> &xfs_efd_item_ops);
> >> @@ -747,9 +742,9 @@ xlog_recover_efd_commit_pass2(
> >>
> >> efd_formatp = item->ri_buf[0].i_addr;
> >> ASSERT((item->ri_buf[0].i_len == (sizeof(xfs_efd_log_format_32_t) +
> >> - ((efd_formatp->efd_nextents - 1) * sizeof(xfs_extent_32_t)))) ||
> >> + (efd_formatp->efd_nextents * sizeof(xfs_extent_32_t)))) ||
> >> (item->ri_buf[0].i_len == (sizeof(xfs_efd_log_format_64_t) +
> >> - ((efd_formatp->efd_nextents - 1) * sizeof(xfs_extent_64_t)))));
> >> + (efd_formatp->efd_nextents * sizeof(xfs_extent_64_t)))));
> >>
> >> xlog_recover_release_intent(log, XFS_LI_EFI, efd_formatp->efd_efi_id);
> >> return 0;
> >> diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
> >> index 0aa87c210104..f58e0510385a 100644
> >> --- a/fs/xfs/xfs_ondisk.h
> >> +++ b/fs/xfs/xfs_ondisk.h
> >> @@ -118,10 +118,10 @@ xfs_check_ondisk_structs(void)
> >> /* log structures */
> >> XFS_CHECK_STRUCT_SIZE(struct xfs_buf_log_format, 88);
> >> XFS_CHECK_STRUCT_SIZE(struct xfs_dq_logformat, 24);
> >> - XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_32, 28);
> >> - XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_64, 32);
> >> - XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_32, 28);
> >> - XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_64, 32);
> >> + XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_32, 16);
> >> + XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_64, 16);
> >> + XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_32, 16);
> >> + XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_64, 16);
> >> XFS_CHECK_STRUCT_SIZE(struct xfs_extent_32, 12);
> >> XFS_CHECK_STRUCT_SIZE(struct xfs_extent_64, 16);
> >> XFS_CHECK_STRUCT_SIZE(struct xfs_log_dinode, 176);
> >> --
> >> 2.27.0
> >>

2021-03-09 22:30:15

by Gustavo A. R. Silva

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Subject: Re: [PATCH][next] xfs: Replace one-element arrays with flexible-array members



On 3/9/21 15:26, Darrick J. Wong wrote:
>>> It seems to work all right for casted NULL pointers, and then we get all
>>> the typechecking and multiplication overflow checking, e.g.:
>>>
>>> size_t len64 = struct_size((struct xfs_efi_log_format_32 *)NULL,
>>> efi_extents src_efi_fmt->efi_nextents);
>> Yeah; in that case, what do you think about casting 0, instead of NULL:
>>
>> uint len32 = struct_size((xfs_efi_log_format_32_t *)0, efi_extents,
>> src_efi_fmt->efi_nextents);
>> uint len64 = struct_size((xfs_efi_log_format_64_t *)0, efi_extents,
>> src_efi_fmt->efi_nextents);
> I don't have a preference either way, either here or for the half-dozen
> more of these scattered elsewhere in the file.

OK. I'll send v2, shortly

Thanks for the feedback!
--
Gustavo